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Sir Benjamin Thompson´s frigate 1781 (With Plans)


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Now this is a real beauty:






Length:                                                                 150'

Breadth:                                                                 39' 6'

Draft of Water Forward                                          15' 9''

Draft of Water Abaft                                               15' 9''

Height of middle gunport above the water:               6' 3''

L/B ratio:                                                                  3,8

Burthen in builder´s tonnage:                             1000 tons

Real Burthen:                                                        915 tons



Armament (proposed):


30*32-pounders  (described as 'light' - 26 CWT, on sliding carriages)

12*12-pounders (also 'light')

20 musketoons on swivel stocks


A battery of 30 long 18s and 8*32-pounder carronades plus 4*9-pounder chase guns would be more realistic, in my opinion.



Sir Benjamin Thompson, probably better known as Count Rumford, made this draught in the late 1770s and sent it, amongst others, to Marmaduke Stalkarrt, who, seemingly impressed by the absolutely innovative design, published it in his 'Naval Architecture or the Rudiments and Rules of Shipbuilding' in 1781.

Although this frigate has never been built, it´s remarkable for it´s V-shaped hull, similiar to Forfait´s 18-pounder frigates built in the 1790s or Symonds' work in the 1830s/1840s.

Edited by Malachi
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I see she's deeper and shorter than a Lively, though.




Shorter, but not deeper. A Lively provisioned for channel service had a draught of 17' 6''/ 19' 6'', even a much smaller Niger sat deeper in the water (14' 8'' / 16' 11').


That deadrise is insanity!

All the more so since it's associated with light vessels, not superheavy armament. Doesn't it affect seakeeping an awful lot?



Jolly good question. The frigates by Simonds from the 1830/1840s like the Vernon  (176' , 44') had a very similiar hull shape and were considered very fast and excellent ships in the right hands. Forfait´s Seine- and Gloire-class also had a V-shaped hull, but with a more conservative deadrise, and were good sea boats, if I remember correctly.


Thompson sent the draught to a couple prominent persons (the list reads like a who-is-who of admirals, shipwrights and mathematicians of the time - Kempenfelt, Douglas, Wells, Barnard, Hutton etc.) for a review and their answers, which are - surprisingly :P - very positive, were also published in 'Naval Architecture'.


The main idea behind this kind of hull shape, according to Thompson, is to reduce the amount of ballast needed (and, logically, the overall displacement) to get a stiff ship and a stable gun platform in all seas. He compared his design to the Lark, a 132', 12-pounder frigate, and the immersed part of the hull is pretty much the same (32784 cubic ft / 32198 cubic feet) and subsequently proposed the masts and rigging of a 32-gun ship. Thompson, a physicist by trade, seems to have been pretty worried about stability.

Edited by Malachi
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Yeah, the 1780s and early 1790 were pretty much the 'golden age' of british shipbuilding - at least aesthetically.

Sleek, elegant lines combined with elaborate, but not excessive carvings.


Here´s the stern and the head in a better resolution:




And two of my other favourites of this era:




Fireship 'Comet' (1783), other ships of this class were converted to ship-sloops, armed with 32-pounder carronades. Considered very fast, based on the french prize Panthère of 1744.




Termagant 1780. 22-gun ship-sloop, armed with 6-pounders. Also a very good sailor, based the french prize Chevert/Pomona of 1759.

Edited by Malachi
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Here´s the quote of the relevant chapter in 'Naval Architecture':


'All the guns upon the main deck are to be thirty-two pounders, upon a new construction, weighing

twenty-six hundreds each, and the quarter deck will be light twelve pounders.


As thirty-two pounder carronades, which are not half so heavy as the the proposed thirty-two pounders, have been proved with very large charges of powder, there can be no doubt that these guns may be made to stand fire with perfect safety; [...]'


As Thompson also experimented with guns and charges, I got the impression that he wanted to design a new type of light naval gun, much like Gover, Salder and Congreve did. And I suppose the sliding carriages would be pretty similiar to Chapman´s design for long guns he made for the Wasa- and Bellona-class. An earlier version of these can be seen on plate XXXIII in the Architectura Navalis Mercatoria.


Edit: The distance between gun ports is 7' 6'' on average, a bit more than what´s usual for 18-pounder frigates - if I remember correctly.

        In terms of weight, the equivalent for his 26 cwt guns (this is without carriage, I suppose) would be 7' 12-pounders (21 cwt), short 18-pounders

        (28 cwt) or 42-pounder carronades (22 cwt).

Edited by Malachi
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Not necessarily. According to Thompson´s calculations, the ship is able to store 4 months of provisions for 250 men with ease and the middle gunport 6' 3'' above the water, which is comparable to french 12- or small 18-pounder frigates of the era.


And I´m very tempted to make a hull model of this ship. I know a guy who has the necessary software to test hydrostatic and hydrodynamic capabilities of 3D ship models, the results might be quite interesting.


Edit: For comparison, here´s a plan of a 36-gun frigate from the 1830s, designed by Symonds (whom I mentioned earlier in this thread).





And a less extreme example of a V-shaped hull, La Révolutionnaire of 1795:



Edited by Malachi
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  • 2 years later...

Hy to all.

I'm not very knowledgeable in aspects of naval architecture and terminology. But I was wondering what sort of armament you are talking here about. Are you referring to 32pd carronades or canons? And one more thing. In your opinion how would she behave if she was to be armed with 24pd long guns on gun deck instead, in terms of speed, maneuverability and stability as a gun platform? 


Edited by Rade
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